Waratahs need more than Izzy firing: Foley

The defiant NSW Waratahs are vowing to storm Christchurch and pull off an "unthinkable" win over Super Rugby's defending champion Crusaders on Saturday.

But playmaker Bernard Foley has warned teammates they can't rely on game-breaking fullback Israel Folau to reignite the Waratahs' spluttering campaign following two straight home defeats.

The Australian conference leaders are suddenly vulnerable after Saturday night's 24-21 loss to the Blues and must conjure at least one win out of a season-defining three-game stretch against the Crusaders and fellow New Zealand heavyweights the Highlanders and Chiefs.

Returning from five weeks out with a hamstring injury, Folau was a shining light for the Tahs with a blinding display in his preferred role of fullback.

So much so that his wife Maria even took to Twitter to ridicule the Wallabies superstar's selection on the wing for his previous two outings.

"OMG @NSWWaratahs why do you keep playing @IzzyFolau on the wing???? ????????????????????????????" the New Zealand netball international posted.

"He's a champion player and that's what we expect of our best players and he showed again tonight why he is a champion," Gibson said.

"Really full of energy. Every time he got the ball he was a real threat, so it's good to have him back."

Foley, though, knows it will take much more than Folau's heroics for the Waratahs to take down the Crusaders and register Australia's first Super Rugby win over a Kiwi outfit in New Zealand since NSW's defeat of the Hurricanes in Wellington in April 2015.

All up, Australian sides have lost 38 straight trans-Tasman clashes in the competition since the Waratahs beat the Chiefs in Sydney in May, 2016.

"Teams are too good now in Super Rugby to allow individuals to go out there and win matches," Foley said.

"You've got to back the guys around you, your 14 other teammates on the field and that's how we'll get the win."

The Wallabies five-eighth doesn't believe the Waratahs have any mental barriers to overcome against Super Rugby's titleholders and 2018 table-toppers.

"It's more about enjoying the grind and not feeling that pressure and playing free, playing the style that we want to play and doing that for 80 minutes.

"We know Kiwi sides are really dangerous on turnovers and set piece they'll hurt you too if you're not switched on, so it's a great challenge for us.

"We know what's ahead of us and we've got to do the unthinkable, which is what other teams aren't going to prepare for us."